So yesterday I came back to this and have done major re-designing of the whole gameplay.

No more directional blocking, only right click + aim to block.

Movement and combat speed set back to base JK2, with some changes in transitions.

Red style enabled and can chain (max 3 swings).

(Also put this in the first post)

The reason was that people generally had problems recognizing directions, animations and to react both to timing and direction at the same time. The slow movement and combat speed also was offputting to many friends and didn't seem like the best approach after all with JK2's movement.
The result was setting it back closer to the core, but with manual blocking. It's still challenging because you have to aim your block (like in Chivalry) and the high damage makes it dangerous to mess up.

Had a good amount of testers today, thanks to (sux)es, elyk der, milka, Cyo, ouned (while it lasted) and Flate.

Conclusion: It works pretty well, is fun 2v2. Yellow chains have good speed, but the initial swings are a bit too fast.
Block/feint timer feels better at 100 than 250. Yellow WA hit can hit inside (through) block if two people stand totally into each other. Changing the animation slightly would most likely fix it if it becomes an issue.

Changes in 2.9a (changes made after testing):
-Feint timer is 100 by default (so you can attack faster after canceling attacks or holding block)
-Yellow start swings are slower and more manageable to react to.